Prostatic cavitary lesions containing urine in dogs

The purpose of this retrospective study was to determine the proportion of urine-containing prostatic cavitary lesions ("urinary cysts") in dogs and to describe their clinical management.

The study included dogs with clinically relevant prostatic-retention cyst/abscess (n=87) treated initially by percutaneous ultrasound-guided drainage of the prostatic cavity. Based on a prostatic fluid:serum creatinine ratio, the study population was divided into two groups: group 1 (n=16) with and group 2 (n=71) without evidence of urine within the lesion. Medical records of both the groups were reviewed.

Cavitary lesions containing urine were observed in 16 of the 87 dogs (18·4%; group 1). In 10 (62·5%) of the group 1 dogs, abdominal surgery was recommended, because of recurrent filling during follow-up. In group 2, abdominal surgery was recommended in only 11 of 71 cases (15·5%).

In dogs, 18·4% (95% confidence interval, 10·9 to 28·1%) of the prostatic cavitary lesions contain urine. Measurement of creatinine within the prostatic cavity fluid is a helpful tool in diagnosing a presurgical intra-prostatic urethral fistulation, and these dogs tend to require a more aggressive surgical therapy than percutaneous drainage alone.